This invention provides an improved hydrostatic transmission of the radial piston type shown in U.S. Pat. No. 3,274,946 Simmons, granted Sept. 27, 1966, and U.S. Pat. No. 3,752,010 Tipping, granted Aug. 14, 1973, and may be used, for example, in the hydrostatic transmission shown in the above U.S. Pat. No. 3,274,946, in hydromechanical transmissions as shown in the above U.S. Pat. No. 3,752,010, or U.S. Pat. No. 3,982,448 Polak et al, granted Sept. 28, 1976, and especially in cross-drive transmissions having a hydrostatic steer-drive transmission unit such as in U.S. Pat. No. 3,373,636 Livezey et al, granted Mar. 19, 1968, and U.S. Pat. No. 3,640,157 Schaefer, granted Feb. 8, 1972. Related controls are shown in the above U.S. Pat. No. 3,640,157.